Micromechanical devices, such as sensors and other components, often comprise moveable elements disposed in or adjacent to cavities within a substrate or other structure. For example, a micro-electromechanical system (MEMS) sensor, such as for sensing pressure, acceleration or some other quantity can have a membrane or mass element disposed in or adjacent to a cavity.
Use of existing CMOS process techniques to form these and other sensors and devices, including those which may incorporate new technology aspects and/or are of increasingly reduced dimensions, can be advantageous with respect to cost and complexity. At the same time, challenges can exist in successfully forming the sensors and devices, both with respect to feature dimensions and such that the membranes, mass elements and other moveable elements are fully formed and separated from adjacent structures such that they can move as designed and the sensor or other device can function properly. A common problem is that moveable elements stick to or are not fully separated from the wall of a cavity in which they are formed, resulting in a nonfunctioning device. Conventional systems and methods for forming these small-scale sensors and devices with sufficient separation of components, however, can be expensive, time-consuming (e.g., having limited etch speed) and still limited by certain dimensions and feature sizes.